NAME
CGI::Application::Plugin::Config::General - Add Config::General Support
to CGI::Application
VERSION
Version 0.08
NOTE
This module is obsolete and has now been superceded by
CGI::Application::Plugin::Config::Context.
SYNOPSIS
Simple Access to Configuration
In your CGI::Application-based module:
use base 'CGI::Application';
use CGI::Application::Plugin::Config::General;
sub cgiapp_init {
my $self = shift;
# Set config file and other options
$self->conf->init(
-ConfigFile => 'app.conf',
);
}
sub my_run_mode {
my $self = shift;
# get entire configuration
my %conf = $self->conf->getall;
# get entire configuration (as a reference)
my $conf = $self->conf->getall;
# get single config parameter
my $value = $self->conf->param('some_value');
# get underlying Config::General::Match object
my $obj = $self->conf->obj;
}
Configuration Based on URL or Module
You can match a configuration section to the request URL, or to the
module name. For instance, given the following configuration file:
admin_area = 0
admin_area = 1
title = Admin Area
title = Feedback Form
The configuration will depend on how the script is called:
# URL: /cgi-bin/feedback.cgi?rm=add
# Module: MyApp::Feedback
print $self->conf->param('admin_area'); # 0
print $self->conf->param('title'); # 'Feedback Form'
# URL: /cgi-bin/admin/users.cgi
# Module: MyApp::Admin::Users
print $self->conf->param('admin_area'); # 1
print $self->conf->param('title'); # 'Admin Area'
Matching Configuration based on a Virtual Host
This module can also pick a configuration section based on the current
virtual-host:
# httpd.conf
SetEnv SITE_NAME REDSITE
# in app.conf
background = blue
foreground = white
background = red
foreground = pink
background = darkgreen
foreground = lightgreen
DESCRIPTION
This module allows you to easily access configuration data stored in
Config::General (i.e. Apache-style) config files.
You can also automatically match configuration sections to the request
URL, or to the module name. This is similar to how Apache dynamically
selects a configuration by matching the request URL to e.g. ""
and "" sections.
You can also select configuration sections based on Virtual Host or by a
variable you set in an ".htaccess" file. This allows you to share a
single application between many virtual hosts, each with its own unique
configuration. This could be useful, for instance, in providing multiple
themes for a single application.
Simple access to Configuration
This module provides a "conf" method to your CGI::Application object.
First, you initialize the configuration system (typically in your
"cgiapp_init" method):
$self->conf->init(
-ConfigFile => 'app.conf',
);
The configuration file is parsed at this point and is available from
this point on.
Then, within your run-modes you can retrieve configuration data:
# get entire configuration
my %conf = $self->conf->getall;
my $value = $conf{'some_value'};
# get entire configuration (as a reference)
my $conf = $self->conf->getall;
my $value = $conf->{'some_value'};
# get single config parameter
my $value = $self->conf->param('some_value');
Multiple named Configurations
You can use more than one configuration by providing a name to the
"conf" method:
$self->conf('database')->init(
-ConfigFile => 'app.conf',
);
$self->conf('application')->init(
-ConfigFile => 'app.conf',
);
...
my %db_config = $self->conf('database')->getall;
my %app_config = $self->conf('application')->getall;
Configuration based on URL or Module
Within your configuration file, you can provide different configurations
depending on the current URL, or on the package name of your
application.
Matches against the "SITE_NAME" environment variable, using an
*exact* match.
# httpd.conf
SetEnv SITE_NAME REDSITE
# in app.conf
background = blue
foreground = white
background = red
foreground = pink
background = darkgreen
foreground = lightgreen
You can use name your sections something other than "", and
you can use a different environment variable than "SITE_NAME". See
"Notes on Site Matching", below.
Matches the Package name of your application module, for instance:
...
The match is performed hierachically, like a filesystem path, except
using "::" as a delimiter, instead of "/". The match is tied to the
beginning of the package name, just like absolute paths. For
instance, given the section:
...
the packages "Site::Admin" and "Site::Admin::Users" would match, but
the packages "My::Site::Admin" and "Site::Administrative" would not.
Matches the package name of your application module, using a regular
expression. The expression is not tied to the start of the string.
For instance, given the section:
...
The following packages would all match: "Site::Admin",
"Site::Admin::Users", "My::Site::Admin", "MySite::Admin",
"Site::Administrative".
Matches hierarchically against the request URI, including the path
and the "PATH_INFO" components, but *excluding* the scheme, host,
port and query string.
So, for instance with the following URL:
http://bookstore.example.com/cgi-bin/category.cgi/fiction/?rm=list
The Location would be:
/cgi-bin/category.cgi/fiction/
Internally, the location is obtained by calling the "url" method of
the query object (which is usually either a CGI or CGI::Simple
object):
$path = $webapp->query->url('-absolute' => 1, '-path_info' => 1);
Matches against the request URI, using a regular expression.
Section Merge Order
The sections are matched in the following order:
Site:
Package Name: and
URL: and
When there is more than one matching section at the same level of
priority (e.g. two "" sections, or both an "" and an
"" section), then the sections are merged in the order of
shortest match first.
Values in sections matched later override the values in sections matched
earlier.
The idea is that the longer matches are more specific and should have
priority, and that URIs are more specific than Module names.
Section Nesting
The sections can be nested inside each other. For instance:
admin_books = 1
admin_records = 1
By default, the sections can be nested up to two levels deep. You can
change this by setting the -NestingDepth parameter to init.
Merging Configuration Values into your Template
You can easily pass values from your configuration files directly to
your templates. This allows you to associate HTML titles with URLs, or
keep text like copyright notices in your config file instead of your
templates:
copyright_notice = Copyright (C) 1492 Christopher Columbus
title = "Manifest Destiny, Inc. - About Us"
title = "Manifest Destiny, Inc. - Contact Us"
If you use HTML::Template, you use the associate method when you load
the template:
$self->load_template(
'template.tmpl',
'associate' => $self->conf,
);
If you use Template::Toolkit (via the CGI::Application::Plugin::TT
module), you can accomplish the same thing by providing a custom
tt_pre_process method:
sub tt_pre_process {
my $self = shift;
my $template = shift;
my $template_params = shift;
my $config = $self->conf->getall
foreach (keys %$config) {
unless (exists $template_params->{$_}) {
$template_params->{$_} = $config->{$_};
}
}
}
*NOTE: If you plan to merge data directly from your config files to
your* *templates, you should consider keeping your database passwords
and other* *sensitive data in a separate configuration file, in order to
avoid* *accidentally leaking these data into your web pages.*
METHODS
init
Initializes the plugin. The only required parameter is a config file:
$self->conf->init(
-ConfigFile => 'app.conf',
);
The other paramters are described below:
-ConfigFile
The path to the configuration file to be parsed.
-Options
Any additional Config::General::Match options. See the documentation
to Config::General and Config::General::Match for more details.
-CacheConfigFiles
Whether or not to cache configuration files. Enabled, by default.
This option is only really useful in a persistent environment such
as "mod_perl". See "Config File Caching" under "ADVANCED USAGE",
below.
-StatConfig
If config file caching is enabled, this option controls how often
the config files are checked to see if they have changed. The
default is 60 seconds. This option is only really useful in a
persistent environment such as "mod_perl". See "Config File Caching"
under "ADVANCED USAGE", below.
-SiteSectionName
Change the name of the "" section to something else. For
instance, to use sections named "", use:
-SiteSectionName => 'VirtualHost'
-SiteVar
Change the name of the "SITE_NAME" environment variable used to
match against "" sections. For instance To change this name to
"HTTP_HOST", use:
-SiteVar => 'HTTP_HOST',
-NestingDepth
The number of levels deep that sections can be nested. The default
is two levels deep.
See "Section Nesting", above.
You can initialize the plugin from within your instance CGI script:
my $app = WebApp->new();
$app->conf->init(-ConfigFile => '../../config/app.conf');
$app->run();
Or you can do so from within your "cgiapp_init" method within the
application:
sub cgiapp_init {
my $self = shift;
$self->conf->init(
-ConfigFile => "$ENV{DOCUMENT_ROOT}/../config/app.conf"
);
}
getall
Gets the entire configuration as a hash or hashref:
my %config = $self->conf->getall; # as hash
my $config = $self->conf->getall; # as hashref
Note that the following two method calls will return different results:
my %config = $self->conf->getall; # parsed config
my %config = $self->conf->obj->getall; # raw config
In the first case, the matching based on URI, Module, etc. has already
been performed. In the second case, you get the raw config with all of
the "", "", etc. sections intact.
param
Allows you to retrieve individual values from the configuration.
It behvaves like the "param" method in other classes, such as CGI,
CGI::Application and HTML::Template:
$value = $self->conf->param('some_key');
@all_keys = $self->conf->param();
obj
Provides access to the underlying Config::General::Match object.
You can access the raw unparsed configuration data by calling
my $config = $self->conf->obj->getall; # raw config
See the note under getall, above.
In future versions of this module, certain caching strategies may
prevent you from accessing the underlying Config::General::Match object
in certain situations.
get_current_config ($name)
This is a class method which returns the current configuration object.
my $conf = CGI::Application::Plugin::Config::General->get_current_config;
print $conf->{'title'};
my %db_conf = CGI::Application::Plugin::Config::General->get_current_config('db');
print $db_conf{'username'};
This method is most useful in situations where you don't have access to
the CGI::Application object, such within a Class::DBI class. See "Access
to Configuration information from another Class" for an example.
Note that get_current_config returns the configuration hash (or hashref)
directly, and does not give you access to the object itself. It is the
equivalent of calling "$self->conf->getall".
ADVANCED USAGE
Usage in a Persistent Environment such as mod_perl
The following sections describe some notes about running this module
under mod_perl:
Config File Caching
By default each config file is read only once when the conf object is
first initialized. Thereafter, on each init, the cached config is used.
This means that in a persistent environment like mod_perl, the config
file is parsed on the first request, but not on subsequent requests.
If enough time has passed (sixty seconds by default) the config file is
checked to see if it has changed. If it has changed, then the file is
reread.
If you are using Config::General version 2.28 or greater, then you can
safely use the "include" feature of Config::General and all included
files will be checked for changes along with the main file.
To disable caching of config files pass a false value to the
-CacheConfigFiles parameter to init, e.g:
$self->conf->init(
-ConfigFile => 'app.conf',
-CacheConfigFiles => 0,
);
To change how often config files are checked for changes, change the
value of the -StatConfig paramter to init, e.g.:
$self->conf->init(
-ConfigFile => 'app.conf',
-StatConfig => 1, # check the config file every second
);
Internally the configuration cache is implemented by a hash, keyed by
the absolute path of the configuration file. This means that if you have
two web applications that use the same configuration file, they will use
the same cache.
This would only matter if you wanted to use different "Config::General"
or "Config::General::Match" options for different applications running
in the same process that use the same config file.
PerlSetVar instead of SetEnv
For a (slight) performance improvement, you can use "PerlSetVar" instead
of "SetEnv" within a "":
# httpd.conf
PerlSetVar SITE_NAME REDSITE
Notes on Site Matching
Renaming "" or "SITE_NAME"
Normally, the environment variable "SITE_NAME" is matched to ""
section.
You can change these with the -SiteSectionName and -SiteVar parameters
to init:
$self->conf->init(
-ConfigFile => 'app.conf',
-SiteSectionName => 'Host',
-SiteVar => 'MY_HOST',
);
This will match the environment variable "MY_HOST" to the ""
section.
Setting "SITE_NAME" from an ".htaccess" file or the CGI script
Since "SITE_NAME" is just an environment variable, you can set it
anywhere you can set environment variables. For instance in an
".htaccess" file:
# .htaccess
SetEnv SITE_NAME bookshop
Or even the calling CGI script:
#!/usr/bin/perl
use MySite::WebApp;
$ENV{'SITE_NAME'} = 'recordshop';
my $app = MySite::WebApp->new();
$app->run();
Access to Configuration information from another Class
You can also get at the current configuration settings from a completely
unrelated Perl module. This can be useful for instance if you need to
configure a set of Class::DBI classes, and you want them to be able to
pick up their configuration on their own. For instance:
# app.conf
connect_string = dbi:Pg:dbname=example
username = test
password = test
RaiseError = 1
AutoCommit = 1
# In your Class::DBI subclass
package My::Class::DBI::Base;
use base 'Class::DBI';
sub db_Main {
my $conf = CGI::Application::Plugin::Config::General->get_current_config;
my $dsn = $conf->{'database'}{'connect_string'};
my $user = $conf->{'database'}{'username'};
my $pass = $conf->{'database'}{'password'};
my $opts = $conf->{'database'}{'options'};
return DBI->connect_cached($dsn, $user, $pass, $opts);
}
For this example to work, you need to make sure you call
"$self->conf->init" before you access the database through any of your
Class::DBI objects.
Note that get_current_config returns the configuration hash (or hashref)
directly, and does not give you access to the object itself. It is the
equivalent of calling "$self->conf->getall".
Changing Parsing Behaviour Using Custom -MatchSections
Internally, this module uses Config::General and Config::General::Match
to parse its config files. If you want to change the parsing behaviour,
you can pass your own -MatchSections list to init. For instance, if you
want to allow only sections named "", with no nesting, and have
these matched exactly to the complete request path, you could do the
following:
# app.conf
admin_area = 0
user_area = 0
admin_area = 1
user_area = 1
# in your cgiapp_init:
$self->conf->init(
-ConfigFile => 'app.conf',
-NestingDepth => 1,
-Options => {
-MatchSections => [
{
-Name => 'URL',
-MatchType => 'exact',
-MergePriority => 0,
-SectionType => 'path',
},
]
}
);
For reference, here is the default -MatchSections:
-MatchSections => [
{
-Name => 'Site', # overridden by -SiteSectionName
-MatchType => 'exact',
-MergePriority => 0,
-SectionType => 'env',
},
{
-Name => 'AppMatch',
-MatchType => 'regex',
-SectionType => 'module',
-MergePriority => 1,
},
{
-Name => 'App',
-MatchType => 'path',
-PathPathSeparator => '::',
-SectionType => 'module',
-MergePriority => 1,
},
{
-Name => 'LocationMatch',
-MatchType => 'regex',
-SectionType => 'path',
-MergePriority => 3,
},
{
-Name => 'Location',
-MatchType => 'path',
-SectionType => 'path',
-MergePriority => 3,
},
],
For each section, the -SectionType param indicates what runtime variable
the section will be matched against. Here are the allowed values
env: matched to the environment variable SITE_NAME (overridden by -SiteNameVar)
module: name of the Perl Module handling this request (e.g. MyApp::Users)
path: path of the request, including path_info (e.g. /cgi-bin/myapp/users.cgi/some/path)
You can use the above -SectionType values in your own custom
-MatchSections.
For more information on the syntax of -MatchSections, see the docs for
Config::General::Match.
AUTHOR
Michael Graham, ""
BUGS
Please report any bugs or feature requests to
"bug-cgi-application-plugin-config-general@rt.cpan.org", or through the
web interface at . I will be notified, and then
you'll automatically be notified of progress on your bug as I make
changes.
ACKNOWLEDGEMENTS
This module would not be possible without Thomas Linden's excellent
Config::General module.
Thanks to the excellent examples provided by the other CGI::Application
plugin authors: Mark Stosberg, Michael Peters, Cees Hek and others.
SOURCE
The source code repository for this module can be found at
http://github.com/mgraham/CAP-Config-General
SEE ALSO
CGI::Application
Config::General
Config::General::Match
CGI::Application::Plugin::Config::Simple
CGI::Application::Plugin::ConfigAuto
CGI::Application::Plugin::TT
Template::Toolkit
HTML::Template
COPYRIGHT & LICENSE
Copyright 2005 Michael Graham, All Rights Reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.